I want full frame, too, but really if you want a full frame camera you should buy one from a company that already makes one. If you keep waiting for Pentax to do it you'll be bound to be disappointed when you could have what you want right now. Maybe Pentax will come out with FF eventually but I'm not holding my breath.

This said, I don't know what a 560 mm f/5.6 being APS-C has anything to do with the prospects of full frame. I imagine it is APS-C to keep its size and price down.